Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The architecture of Stack Overflow [video]

dev-metal.com

Post reply on HN
Print view View original

41–49 of 49 posts

Re: The architecture of Stack Overflow [video]

#41

Post by jaydles »

thedufer wrote: post #39
kmontrose wrote: post #16

Earlier quoted context omitted.

The Stack Overflow Q&A dev team has 2 people in New York, out of a team of 10 team. The Careers dev team is more New York heavy, 3 remote and 5 in New York. The sysadmin team is also quite remote, though I don't know the breakdown offhand. I believe at this point most new technical hires are remote. Our offices are mostly sales, Denver and London exclusively so.

I saw that Jason went remote recently. Any particular reason so many devs are going remote? Is it people making individual decisions or the company providing new incentives to do so? My impression when you were at 55 was that most devs worked at the office (I've been at Fog Creek since a little before you guys moved. Hi!).

People making individual decisions. All else equal, we'd slightly prefer to have people in NYC, because we think the in-person time is a plus for the casual interaction that happens in between "getting things done". But we've set our selves up to make real work and official team collaboration work almost entirely online. We've learned that the in-person benefit is more than outweighed by how much you get from being able to hire the best talent that loves the product anywhere, not just the ones willing to live in the city you happen to be in.

Re: The architecture of Stack Overflow [video]

#42

Post by TacticalCoder »

alexgartrell wrote: post #35

Dear any Stack Overflow Developers, Can you describe the network infrastructure in finer detail? Specifically what type of load balancer are you running? And what's peak RPS? Where are your network peaks? (I'm guessing major peak US Pacific and minor US Atlantic?)

IIRC at first they had an entire Microsoft stack (I may be mistaken on that).

But nowadays, from what I've read here on HN by SE devs in other threads, they're using lots and lots and lots of Linux: HAProxy, Redis, Nagios, etc.

I just double-checked the slide and although I didn't notice it at first, you can see that 'HA Proxy' and 'Redis' are mentioned.

The core Q&A is in C#/MS-SQL so that's probably not going to move to Linux anytime soon.

Re: The architecture of Stack Overflow [video]

#43

Post by skeletonjelly »

carsongross wrote: post #10
WestCoastJustin wrote: post #6

Earlier quoted context omitted.

Having a great Ops staff also helps ;) Of note is Thomas Limoncelli who wrote "The Practice of System and Network Administration" [1] and "Time Management for System Administrators" [2] works for Stack Exchange (formerly at Google). The Practice of System and Network Administration is basically the bible for most sysadmins, myself included. ps. I only singled Thomas Limoncelli out as an example just to highlight the…

Violently agree.

Vehemently? Or do you want to punch someone?

Re: The architecture of Stack Overflow [video]

#44

Post by avemg »

kmontrose wrote: post #22
zero1zero wrote: post #20

Earlier quoted context omitted.

I would like to know more about this as well. It sounds like they are all SQL Server instances. However, he made it seem like they are reproducing the schema once per site? I.e., a separate database per site rather than sharding the shared data to multiple hosts per site. Did I hear this right in the question/answer portion?

Stack Exchange has one database per-site, so Stack Overflow gets on, Super User gets one, Server Fault gets one, and so on. The schema for these is the same. There are a few wrinkles. There is one "network wide" database which has things like login credentials, and aggregated data (mostly exposed through stackexchange.com user profiles, or APIs). Careers Stack Overflow, stackexchange.com, and Area 51 all have their o…

How do you manage schema changes with release deployments across across all of the databases that are meant to be standard?

Re: The architecture of Stack Overflow [video]

#46

Post by sklivvz1971 »

avemg wrote: post #44
kmontrose wrote: post #22

Earlier quoted context omitted.

Stack Exchange has one database per-site, so Stack Overflow gets on, Super User gets one, Server Fault gets one, and so on. The schema for these is the same. There are a few wrinkles. There is one "network wide" database which has things like login credentials, and aggregated data (mostly exposed through stackexchange.com user profiles, or APIs). Careers Stack Overflow, stackexchange.com, and Area 51 all have their o…

How do you manage schema changes with release deployments across across all of the databases that are meant to be standard?

All the schema changes are applied to all site databases at the same time. They need to be backwards compatible so, for example, if you need to rename a column - a worst case scenario - it's a multiple steps process: add a new column, add code which works with both columns, back fill the new column, change code so it works with the new column only, remove the old column.

Re: The architecture of Stack Overflow [video]

#47

Post by dan_b »

skittles wrote: post #25

He mentioned that they use the servicestack.text library. I've looked into servicestack recently (using the nuget packages), but then found the library to be pay-to-play. There's an older version (v3) that is BSD licensed that is being maintained. Do any of you have experience with it? I have grown tired of Microsoft pushing new solutions to the same problem (REST service with WCF and then Asp.net web api).

ServiceStack is just plain awesome when it comes to developing web services, though it's gone commercial for v4 onward. Nancy is another popular alternative - it's basically Sinatra for .Net. Every time I go back to WCF I want to stab myself in the face.

Re: The architecture of Stack Overflow [video]

#48

Post by avemg »

sklivvz1971 wrote: post #46
avemg wrote: post #44

Earlier quoted context omitted.

How do you manage schema changes with release deployments across across all of the databases that are meant to be standard?

All the schema changes are applied to all site databases at the same time. They need to be backwards compatible so, for example, if you need to rename a column - a worst case scenario - it's a multiple steps process: add a new column, add code which works with both columns, back fill the new column, change code so it works with the new column only, remove the old column.

Thanks for the reply. We have a similar architecture where I work so this is interesting to me. A couple more questions if you don't mind:

- Do you use any tools for orchestrating the rollout of those schema changes or do you just have some homegrown scripts?

- Do you separate your schema versioning and deployment process from your application versioning and deployment process?

- How do you handle cases where backwards-compatibility is not possible? For example, a new application feature that depends on a brand new table.

Post reply on HN